Meteorologist - Professor
                                          
"Thunderstorms"


Thunderstorms generated by temperature imbalances in the 
atmosphere are a violent example of convection.

               "Thunderstorms Occur In 3 Stages"

   1st Stage...Cumulus. 2nd Stage...Mature. 3rd Stage...Dissipating

In the first stage (Cumulus) of thunderstorm development an updraft 
warms air up to where the water vapor it contains condenses into visible 
droplets and a cloud is formed.

As the clouds form, water vapor changes to liquid and or frozen cloud 
particles. This results in a release of heat, (Latent Heat) that takes 
over as the principal source of energy for the developing cloud. As the 
cloud particles grow by colliding and combining (Coalescence) with each
 other, they may become rain, snow, or hail. 

In the 2nd Stage (Mature) precipitation which has developed falls creating 
a downdraft. The cumulonimbus cloud (CB) has now formed. The cloud now 
contains an updraft & downdraft. 

The thunderstorm may be several miles across its base and often towers 
to altitudes 40,000 to 50,000 feet or more and may well reach into the 
stratosphere.

The 3rd Stage. "Dissipating". This stage is marked by a change in wind 
flow within the storm cell. 

The prevailing updraft which initiated the cloud's growth is now 
replaced by the downdraft. 

On the ground directly beneath the storm system, this stage is often 
accompanied by strong gusts and cold wind from the downdraft, or
 heavy precipitation - rain or hail. These downdrafts may well reach
 over 100 mph and are called (Microbursts or Downbursts)

Lightning always accompanies the thunderstorm. These are nature's 
 warning that the thunderstorm is in it's most violent stage.
  
Tornadoes may also be associated with the thunderstorm.


In the 3rd stage, however, the thunderstorm cell has already begun to 
die.

The violent downdraft having shared the circulation with the updraft
 now strangles it.

Precipitation weakens and the thunderstorm, a short lived creature,
 weakens and dies.

From the 1st stage of a thunderstorm to when the storm dies all takes 
place in about 30 minutes to an hour. 


1. On earth, 2,000+ thunderstorms occur each hour. 40,000 to 50,000 
   each 24 hours, most     
   occurring near the equator. Millions and millions of lightning 
   strikes each 24 hours

2. Thunderstorms reach up into the stratosphere 50,000 to 60,000 feet.

3. The name given to a thunderstorm is: Cumulonimbus. CB

4. Cumulus meaning puffy. Nimbus meaning rain.

5. The average thunderstorm lasts about 30 minutes to an hour, 
   and may or may not be     accompanied by hail.